Retired judge and San Francisco Ethics Commissioner Quentin Kopp on Tuesday announced the filling of a lawsuit in U.S. Federal Court against the U.S. Secret Service for public records related to Donald Trump Jr.’s protection detail while on a private fundraising trip to India. (Kevin N. Hume/S.F. Examiner)

In an attempt to prove Donald Trump Jr. misused taxpayer dollars on a business trip to India, San Francisco Ethics Commissioner Quentin Kopp on Tuesday sued the U.S. Secret Service for refusing to disclose how much it cost to protect the president’s son.

The lawsuit, filed in U.S. District Court in San Francisco, claims that taxpayers should not foot the bill for the protection of the adult children of President Donald Trump on trips that profit the Trump Organization.

The lawsuit centers around a February trip in which Trump Jr. traveled to India to promote real estate sales for the Trump Organization and to deliver a foreign policy speech that was later canceled, according to the Washington Post. The trip raised conflict of interest concerns — and $15 million for the company in a day.

“It’s private business at the expense of taxpayers,” Kopp told reporters outside the federal courthouse in San Francisco. “I’m a taxpayer. I resent it.”

Kopp, a member of the California First Amendment Coalition Board of Directors, filed a public records request under the Freedom of Information Act in February in an attempt to find out how many Secret Service agents accompanied Trump Jr. on the trip and what costs such as lodging and transportation were incurred.

The Secret Service responded in May that the request was too broad. Kopp responded with further details, but has not heard back since.

That prompted Kopp to file the lawsuit. The retired judge, city supervisor and state senator said the information could lead to further lawsuits.

“There’s been a wholesale use of taxpayer assets by the Trump family led by the President of the United States,” Kopp said. “It’s almost as if he’s acting in the true form of a crook to take taxpayer money and to use it for private business.”

A spokesperson for the U.S. Attorney’s Office had not seen the complaint and declined to comment.